FEG ESEM – FEI Quanta 400

The field emission (FEG) ESEM is a first pass analysis tool for characterising mineral/mineral processing problems on a variety of samples.  The instrument can operate in three different modes: 

  • high vacuum – for ultimate resolution and enables full elemental quantification,  
  • low vacuum – minimal sample preparation for imaging and qualitative analysis, 
  • full environmental mode – for characterisation of hydrated samples.  

These modes allow the examination of the broadest range of samples possible today in electron microscopy, from non-conductive ores and concentrates to wet clays. A range of detectors including imaging (secondary and backscattered electron), chemical analysis (energy dispersive x-ray analysis) and structural (Electron Backscattered Diffraction) mean that the FEG ESEM is the ideal starting point for sample characterisation.

At a glance:

  •  

    Field emission gun
  • Environmental SEM capabality
  • Bruker e– Flash, EBSD with fore and back scattered diodes
  • Bruker X-Flash EDS 10 mm2 silicon drift (SDD-EDS)
  • Hot stage

 

The Bruker e– Flash, EBSD system uses a conventional CCD camera for its imaging of the diffraction pattern. It has a maximum resolution of 1600 × 1200 pixels and can be binned down to 80 × 60 pixels (20 × 20 binning). The maximum speed is 140 Hz and, with an optimally prepared sample, can be run at this speed with 10 × 10 binning or even 5 × 5 binning. The detector also has a variable tilt option which enables it to operate at different working distances.

The Bruker X-Flash EDS detector is a 10 mm2, silicon drift, EDS system also capable of high throughput, good peak resolution (127 eV at Mn Ka), light element detection (down to Be) and hyperspectral mapping.

Fully standardised EDS analysis can also be done on both systems using CSIRO Mineral Resources’ proprietary software (MQuant). Furthermore, the system is equipped with fore scattered (FSD) and back scattered (BSD) diodes to enhance detection and display of microstructural features such as grain boundaries and twins.

The Bruker e-Flash and X-flash systems are supported by the latest Bruker Esprit 2.2 software. This system is also capable of simultaneous acquisition of EBSD and EDS datasets and can also use the EDS data to assist with indexing of EBSD datasets. The Bruker system comes standard with the very latest International Crystal Structure Database (ICSD) license, as well as the latest American Mineralogist Crystal Structure Database (AMSCD) license. The latest versions of these two critical databases include unit cell data for many thousands of individual phases and provide scope to analyse the broadest possible range of phases.

The software supports analysis of individual grain orientation, grain size and distribution data, grain boundary and coincident site lattice (CSL) information, preferred orientation information (pole figures, inverse pole figures and orientation distribution functions (ODF’s)) and phase identification.